Add environmental variable that strips xbr.

[jameshilliard]

This will create distributions and installations without xbr when the env variable AUTOBAHN_STRIP_XBR is set.

[oberstet]

ok, cool! this looks like it addresses all concerns .. the added (amount of) lines: we can handle that .. not too much hassles/work.

so as you mentioned somewhere, yeah, xbr isn't yet broadly used .. should have little external effect. our own stuff: I don't expect much now .. it's non-intrusive .. let's see;)

thanks for your time and work in contributing!

[jameshilliard]

Thanks, by the way it's probably still a good idea to split the contracts out into a separate repo in addition to this change, mostly just so that autobahn downloads are faster as autobahn is a dependency for many projects, that's more of an issue for non-buildroot usages of autobahn(docker images for example) however as buildroot cross compiles packages on a host system and installs to the target image.

Buildroot downloads a large amount of code during a build anyways so the size doesn't make a huge difference on the download size, it's the target installation size that's the big issue, buildroot tightly controls what actually ends up on the target image to keep things small.

[oberstet]

it's probably still a good idea to split the contracts out into a separate ..

.. package

#1375